1. Field of the Invention
The present invention is directed to a hearing aid of the type having at least one microphone, a signal processing unit with a series of signal processing stages, a signal output transducer, a memory in which at least one set of parameters allocated to a hearing situation can be stored, which, when the hearing situation is present, enables matching of the parameters of the signal processing stages to the wearer's hearing impairment, and adjustment means for individually matching the respective signal processing stages.
2. Description of the Prior Art
A hearing aid of the above type is known from German OS 44 19 901, whose operation and/or control ensues by means of code words spoken by the hearing-impaired person. For this purpose, in a programmable embodiment of the hearing aid, transmission characteristics matched to different hearing situations/environmental situations are stored, which can be selected by means of allocated code words such as e.g. "program 1" or "program 2." Such a hearing aid must be individually matched (configured) by a hearing aid acoustician, using a programming device, at the time it is first given to the hearing-impaired person. This makes the use of such hearing aid devices impossible in countries that do not have the necessary infrastructure (state of technical development, availability of PCs, etc.).
From German OS 43 32 250, a programmable hearing aid is known that can be switched to two different environmental acoustic situations. For this purpose, two circuits are connected via switching means. This connection enables switching of predetermined matching parameters to the different environmental situation. The adjustment means, however, remain dependent on the signal processing stages; exchange takes place only between predetermined matching parameters. The hearing aid requires programming for the individual matching, and in addition is of expensive construction.
German OS 36 42 828 discloses a remotely controllable programmable hearing aid in which a first memory contains a number of programs for parameters representing different transmission characteristics of the hearing aid, as well as a control panel for the selective construction of each set of parameters. This hearing aid also has to be programmed individually upon being issued to the hearing-impaired person.
A programmable circuit for hearing aids is known from European Application 0 676 909. This circuit is distinguished by low power consumption and versatility of use. This is achieved because only those signal processing stages, such as e.g. filters, preamplifier, AGC and the like, that are required for the specific application, are activated by programming. In addition, the parameters of the signal processing stages, such as e.g. amplification, are determined in this programming process. A disadvantage of this known circuit is that the settings are exclusively programmable, thus a modification, e.g., of filter bandwidth or AGC threshold, requires the presence of corresponding technical infrastructure and expert knowledge.